Light source device and display unit

ABSTRACT

A light source device includes: a substrate; a plurality of light sources disposed on the substrate; a wavelength conversion member disposed to face the plurality of light sources; and a diffusion member disposed between the wavelength conversion member and the plurality of light sources, and configured to uniformize distribution of traveling direction angle of incident light.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese Priority PatentApplication JP 2013-159328 filed Jul. 31, 2013, the entire contents ofwhich are incorporated herein by reference.

BACKGROUND

The present disclosure relates to a light source device suitable for aplanar light source and to a display unit performing image display withuse of illumination light from the light source device.

Backlight system used in a liquid crystal display unit and the likeincludes a direct system and an edge light system. As these backlights,in recent years, a light emitting diode (LED) is often used for a lightsource. When the LED is used as the light source, for example, there isa method in which surroundings of a blue LED is sealed by a resincontaining a fluorescent substance to mix blue light and light emittedfrom the fluorescent substance, and thus white light is obtained. Asanother method, there is a method in which a fluorescent substance layeris disposed separately from the light source to obtain white light(Japanese Unexamined Patent Application Publication No. 2009-140829).

SUMMARY

The backlight as described above desirably has high uniformity as aplanar light source. For example, uniform white light less in colorunevenness and luminance unevenness may be desired. In the JapaneseUnexamined Patent Application Publication No. 2009-140829, althoughthere is proposed that a light control section that allows light from alight emitting element to enter a light emission surface of thefluorescent substance layer from a vertical direction or a substantiallyvertical direction is included and viewing angle dependency ofchromaticity distribution of the fluorescent substance layer issuppressed, illumination light with higher quality is desired.

It is desirable to provide a light source device and a display unit thatare capable of improving quality of illumination light.

According to an embodiment of the technology, there is provided a lightsource device including: a substrate; a plurality of light sourcesdisposed on the substrate; a wavelength conversion member disposed toface the plurality of light sources; and a diffusion member disposedbetween the wavelength conversion member and the plurality of lightsources, and configured to uniformize distribution of travelingdirection angle of incident light.

According to an embodiment of the technology, there is provided adisplay unit provided with a light source device configured to emitillumination light and a display section configured to display an imagebased on the illumination light from the light source device. The lightsource device includes: a substrate; a plurality of light sourcesdisposed on the substrate; a wavelength conversion member disposed toface the plurality of light sources; and a diffusion member disposedbetween the wavelength conversion member and the plurality of lightsources, and configured to uniformize distribution of travelingdirection angle of incident light.

In the light source device and the display unit according to therespective embodiments of the disclosure, the distribution of thetraveling direction angle of the incident light is uniformized by thediffusion member disposed between the wavelength conversion member andthe plurality of light sources.

In the light source device and the display unit according to therespective embodiments of the disclosure, the diffusion member isdisposed between the wavelength conversion member and the plurality oflight sources. Therefore, it is possible to improve quality ofillumination light.

Note that the effects described here are not necessarily limited, andany effect described in the present disclosure may be obtained.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary, and are intended toprovide further explanation of the technology as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure, and are incorporated in and constitutea part of this specification. The drawings illustrate embodiments and,together with the specification, serve to explain the principles of thetechnology.

FIG. 1 is a sectional diagram illustrating a structure example of alight source device according to a first embodiment of the disclosure.

FIG. 2 is a plan view illustrating an example of an in-plane arrangementof light sources in the light source device according to the firstembodiment.

FIG. 3 is a sectional diagram illustrating a structure example of thelight source and its surroundings in the light source device accordingto the first embodiment.

FIG. 4 is a sectional diagram illustrating a structure example of awavelength conversion sheet in the light source device according to thefirst embodiment.

FIG. 5 is a sectional diagram illustrating an example of a travelingstate of light in the inside of the light source device according to thefirst embodiment.

FIG. 6 is an explanatory diagram illustrating a first example of thetraveling state of light that enters the wavelength conversion sheetfrom the light sources.

FIG. 7 is an explanatory diagram illustrating a second example of thetraveling state of the light that enters the wavelength conversion sheetfrom the light sources.

FIG. 8 is a sectional diagram illustrating the traveling state of lightthat enters the wavelength conversion sheet from a vertical direction.

FIG. 9 is a sectional diagram illustrating the traveling state of lightthat enters the wavelength conversion sheet from an oblique direction.

FIG. 10 is a sectional diagram illustrating a function of a diffusionmember in the light source device according to the first embodiment.

FIG. 11 is a sectional diagram illustrating a structure example of alight source device according to a first modification of the firstembodiment.

FIG. 12 is a plan view illustrating a first structure example of adiffuser with a shaped surface.

FIG. 13 is a plan view illustrating an example of a light source imageformed by the diffuser with the shaped surface illustrated in FIG. 12.

FIG. 14 is a plan view illustrating a second structure example of thediffuser with the shaped surface.

FIG. 15 is a plan view illustrating an example of a light source imageformed by the diffuser with the shaped surface illustrated in FIG. 14.

FIG. 16 is a sectional diagram illustrating a structure example of alight source device according to a comparative example.

FIG. 17 is a sectional diagram illustrating a structure example of alight source device according to a second modification of the firstembodiment.

FIG. 18 is a sectional diagram illustrating a structure example of alight source of the light source device according to the secondmodification of the first embodiment.

FIG. 19 is a sectional diagram illustrating a structure example of alight source device according to a second embodiment.

FIG. 20 is a sectional diagram and a plan view each illustrating astructure example of a prism sheet in the light source device accordingto the second embodiment.

FIG. 21 is a sectional diagram illustrating a function of the prismsheet in the light source device according to the second embodiment.

FIG. 22 is a sectional diagram illustrating a structure example of alight source device according to a third embodiment.

FIG. 23 is a sectional diagram illustrating a function of a cut filterin the light source device according to the third embodiment.

FIG. 24 is a sectional diagram illustrating a first structure example ofa light source device according to a modification of the thirdembodiment.

FIG. 25 is a sectional diagram illustrating a second structure exampleof the light source device according to a modification of the thirdembodiment.

FIG. 26 is an appearance diagram illustrating an example of a displayunit.

DETAILED DESCRIPTION

Hereinafter, preferred embodiments of the disclosure will be describedin detail with reference to drawings. Note that description will begiven in the following order:

1. First embodiment (a structure example in which a diffusion member isdisposed)

-   -   1.1 Structure    -   1.2 Function    -   1.3 Effects    -   1.4 Modification of first embodiment    -   1.4.1 First modification (a structure example in which a        diffuser with a shaped surface is disposed as a diffusion        member)    -   1.4.2 Second modification (a structure example in which direct        potting type light sources are disposed)

2. Second embodiment (a structure example in which a prism sheet isadditionally disposed)

-   -   2.1 Structure    -   2.2 Function and effects

3. Third embodiment (a structure example in which a cut filter isadditionally disposed)

-   -   3.1 Structure and function    -   3.2 Modification of third embodiment

4. Numerical examples

5. Other embodiments

1. First Embodiment (1.1 Structure)

FIG. 1 illustrates a structure example of a light source deviceaccording to a first embodiment of the disclosure. FIG. 2 illustrates anexample of an in-plane arrangement of light sources 2 of the lightsource device. FIG. 3 illustrates a structure example of the lightsource 2 and its surroundings. FIG. 4 illustrates a structure example ofa wavelength conversion sheet 3 of the light source device. The lightsource device is suitable as a planar light source, and may be used as,for example, a direct type backlight.

The light source device includes a light source substrate 1, a pluralityof light sources 2, the wavelength conversion sheet 3 serving as awavelength conversion member, a diffusion member 4, an optical sheet 5,a reflective sheet 6 serving as a reflection member, a resist layer 7, aback chassis 101, and a middle chassis 102.

The light source substrate 1 is disposed on a bottom surface of the backchassis 101. The back chassis 101 has a shape in which a peripheral partfolded upward, and the middle chassis 102 is attached to an end of theperipheral part. In the peripheral part of the back chassis 101, a flatpart is formed inside the part attached to the middle chassis 102, and aperipheral part of the diffusion member 4 is supported by the flat part.The wavelength conversion sheet 3 and the optical sheet 5 are disposedon a light emission surface (a front surface) side of the diffusionmember 4. When the light source device is applied to a display unit, adisplay panel may be disposed on a light emission surface (a frontsurface) side of the optical sheet 5. In such a case, a peripheral partof the display panel may be supported by the middle chassis 102.

The wavelength conversion sheet 3 is disposed so as to face theplurality of light sources 2. The diffusion member 4 is disposed betweenthe wavelength conversion sheet 3 and the plurality of light sources 2.The diffusion member 4 is to uniformize distribution of travelingdirection angle of incident light. As the diffusion member 4, onediffusion plate or one diffusion sheet may be used, or two or morediffusion plates or two or more diffusion sheets may be used.

The optical sheet 5 is disposed on a light emission surface (a frontsurface) side of the wavelength conversion sheet 3. For example, theoptical sheet 5 may be formed of a sheet or a film to improve luminance.For example, the optical sheet 5 may include a prism sheet. In addition,the optical sheet 5 may include a reflection type polarization film suchas a dual brightness enhancement film (DBEF).

On the light source substrate 1, a not illustrated wiring pattern isformed to allow independent light emission control for every one orevery two or more light sources 2. Therefore, local light emissioncontrol (local dimming) of the plurality of light sources 2 is allowedto be performed. As the light source substrate 1, a resin film such aspolyethylene terephthalate (PET), fluorine, and polyethylene naphthalate(PEN) that is printed with a wiring pattern may be used. In addition, ametal base substrate such as aluminum (Al) that has a polyimide orepoxy-based insulation resin layer on a surface and is printed with awiring pattern of a material having a light reflectivity on theinsulation resin layer may be used. Moreover, a film substrate formed ofa glass-containing resin such as glass epoxy resin (FR4) and glasscomposite resin (CEM3) on which a wiring pattern of the material havinglight reflectivity is printed may be used. Examples of the materialhaving light reflectivity may include, for example, Al, silver (Ag), andan alloy thereof.

The resist layer 7 and the reflective sheet 6 are disposed in order onthe light source substrate 1. The reflective sheet 6 is disposed in anin-plane region that is different from in-plane regions provided withthe plurality of light sources 2 on the light source substrate 1.

The resist layer 7 is a white resist layer relatively high inreflectance to light from the light sources 2 and light that iswavelength-converted by the wavelength conversion sheet 3. Examples ofwhite resist may include, for example, inorganic materials such astitanium oxide (TiO₂) microparticles and barium sulfate (BaSO₄)microparticles, and organic materials such as porous acrylic resinmicroparticles having myriad of holes for light scattering, andpolycarbonate resin microparticles.

The reflective sheet 6 has a high reflectance to the light from thelight sources 2 and the light that is wavelength-converted by thewavelength conversion sheet 3. The reflective sheet 6 may contain Ag asa material having high reflectance. As illustrated in FIG. 2 and FIG. 3,through holes 61 to dispose the light sources 2 are formed in thereflective sheet 6.

In the in-plane region provided with the through holes 61, the resistlayer 7 is exposed around the light sources 2. Therefore, the outermostsurface of the light source substrate 1 is the reflective sheet 6 in thein-plane region other than the through holes 61, and is the lightsources 2 and the resist layer 7 in the in-plane regions provided withthe through holes 61.

As illustrated in FIG. 2, the light sources 2 are two-dimensionallyarranged on the light source substrate 1. As illustrated in FIG. 3, eachof the light sources 2 includes a light emitting element 21, a package22, and a sealant 23. The package 22 has a concave housing part, and thelight emitting element 21 is disposed on a bottom surface of the concavehousing part. The concave housing part is filled with the sealant 23.For example, the light emitting element 21 may be a point light source,and specifically configured of an LED. The package 22 is mounted on thelight source substrate 1 by solder or the like, through an externalelectrode formed of lead frame or the like (not illustrated). A frontsurface of the concave housing part of the package 22 may preferablyhave high reflectance to light from the light emitting element 21. Thefront surface of the concave housing part may contain, for example, Agas a material having high reflectance. For example, the sealant 23 maybe formed of a transparent resin such as silicone and acryl.

As illustrated in FIG. 4, the wavelength conversion sheet 3 includes awavelength conversion material 31. For example, the wavelengthconversion material 31 may contain fluorescent substance (fluorescentmaterial) such as fluorescent pigment and fluorescent dye, or quantumdots. The wavelength conversion material 31 is excited by the light fromthe light sources 2, and converts a wavelength of the light from thelight sources 2 into a different wavelength through principle offluorescent light emission or the like, and emits the light.

The light source 2 may be, for example, a blue light source (forexample, wavelength of 440 nm to 460 nm), and the wavelength conversionmaterial 31 absorbs blue light from the light source 2 and converts partof the absorbed light into red light (for example, wavelength of 620 nmto 750 nm) or green light (for example, wavelength of 495 nm to 570 nm).In this case, when the light from the light source 2 passes through thewavelength conversion material 31, red, green, and blue light aresynthesized to generate white light. Moreover, the wavelength conversionmaterial 31 may absorb the blue light to convert part of the absorbedlight into yellow light. In this case, when the light from the lightsource 2 passes through the wavelength conversion material 31, yellowand blue light are synthesized to generate white light.

The wavelength conversion material 31 may preferably contain the quantumdots. The quantum dots are particles each having a diameter of about 1nm to about 100 nm, and have discrete energy level. Since the energystate of the quantum dots depends on the size, changing the size makesit possible to freely select light emission wavelength. Moreover, lightemitted from the quantum dots has a narrow spectrum width. Color gamutis expanded by combination of such light having steep peak. Therefore,using the quantum dots for the wavelength conversion material 31 makesit possible to easily expand the color gamut. Further, the quantum dotshave high responsiveness, which makes it possible to efficiently utilizethe light from the light sources 2. In addition, the quantum dots havehigh stability. For example, the quantum dots may be a compound of group12 elements and group 16 elements, a compound of group 13 elements andgroup 16 elements, or a compound of group 14 elements and group 16elements, and may be, for example, CdSe, CdTe, ZnS, CdS, PbS, PbSe,CdHgTe, or the like.

(1.2 Function) (Function of Entire Light Source Device)

FIG. 5 illustrates an example of a traveling state of light in theinside of the light source device. In the light source device, part oflight LB (for example, blue light) emitted from the light source 2becomes light LY that is wavelength-converted (is emitted) by thewavelength conversion material (FIG. 4) in the wavelength conversionsheet 3. The wavelength-converted light LY may be, for example, redlight and green light, or yellow light. The wavelength-converted lightLY is averagely and uniformly reflected and emitted in all directionsfrom the wavelength conversion sheet 3. Out of the light LB emitted fromthe light source 2, light LB3 that collides against the wavelengthconversion material 31 and is not absorbed is also averagely anduniformly reflected and emitted in all directions from the wavelengthconversion sheet 3. Out of the light LB emitted from the light source 2,light LB2 that does not collide against the wavelength conversionmaterial 31 is emitted as it is from the wavelength conversion sheet 3.Light directed frontward out of the light LB2 and LB3 that are notwavelength-converted and light directed frontward out of thewavelength-converted light LY are synthesized to generate white light,and the white light is emitted frontward (to the outside of the lightsource device).

Moreover, part of the light LB2 and LB3 that are notwavelength-converted becomes light (downward light LB1) directedrearward (the substrate 1 side) from the wavelength conversion sheet 3.Furthermore, part of the light directed frontward out of the light LB2and LB3 that are not wavelength-converted becomes recurrent light by theoptical sheet 5 such as DBEF, and becomes the downward light LB1. Thedownward light LB1 is reflected by the front surface (mainly thereflective sheet 6) of the light source substrate 1 and directs towardthe wavelength conversion sheet 3 again, and part thereof iswavelength-converted. Likewise, downward light LY1 out of thewavelength-converted light LY is reflected by the front surface of thelight source substrate 1 and thus becomes light directed frontward. Inthis way, the downward light LB1 and LY1 are reflected by the frontsurface of the light source substrate 1, and thus become recycle lightto generate white light. The recycle of the downward light LB1 and LY1may be performed, for example, four or five times in some cases.Therefore, final luminance of the white light emitted from the lightsource device is obtained from the light containing the recycle light.

(Function of Diffusion Member 4)

A function of the diffusion member 4 is described with reference to FIG.6 to FIG. 10. FIG. 6 illustrates a first example of the traveling stateof the light that enters the wavelength conversion sheet 3 from thelight sources 2. FIG. 7 illustrates a second example of the travelingstate of the light that enters the wavelength conversion sheet 3 fromthe light sources 2. FIG. 6 and FIG. 7 each illustrate a structure fromwhich the diffusion member 4 is omitted. FIG. 8 illustrates thetraveling state of light that enters the wavelength conversion sheet 3from a vertical direction. FIG. 9 illustrates the traveling state oflight that enters the wavelength conversion sheet 3 from an obliquedirection. FIG. 10 illustrates the function of the diffusion member 4.

FIG. 6 illustrates a case where an arrangement distance D of theplurality of light sources 2 is optimized to an appropriate distance aswell as a distance H between the plurality of light sources 2 and thewavelength conversion sheet 3 is optimized to an appropriate value. Inthis case, in the wavelength conversion sheet 3, for example, in aregion 81 directly above the light source 2, a vertical component L1 andan oblique component L2 of the light from the light source 2 areuniformly mixed to generate white light. In the case where the diffusionmember 4 is not disposed, to establish a state where the verticalcomponent L1 and the oblique component L2 of the light from the lightsource 2 are uniformly mixed, it is necessary to make the arrangementdistance D of the plurality of light sources 2 small to some extent. Inaddition, it is necessary to make the distance H between the pluralityof light sources 2 and the wavelength conversion sheet 3 long to someextent.

On the other hand, FIG. 7 illustrates a case where the arrangementdistance D of the plurality of light sources 2 is larger and thedistance H between the plurality of light sources 2 and the wavelengthconversion sheet 3 is smaller, as compared with the state in FIG. 6. Inthis case, for example, in a region 82 directly above the light source2, a ratio of the oblique component L1 of the light from the lightsource 2 may become large. In addition, for example, in a region 83deviated from directly above the light source 2, a ratio of the obliquecomponent L2 of the light from the light source 2 may become large. Inthis case, as illustrated in FIG. 8 and FIG. 9, a difference occursbetween an optical path through which the vertical component L1 passesand an optical path through which the oblique component L2 passes, inthe inside of the wavelength conversion sheet 3, which results indifference in a ratio at which the light collides against the wavelengthconversion material 31. Therefore, difference occurs in the ratio of thelight wavelength-converted by the wavelength conversion material 31.Since the optical path through which the oblique component L2 passes islonger than the optical path through which the vertical component L1passes, the ratio of the light wavelength-converted by the wavelengthconversion material 31 becomes large. Accordingly, color unevenness inwhich chromaticity is different between the region 82 directly above thelight source 2 and the region 83 deviated from directly above the lightsource 2 occurs.

Displacement of the diffusion member 4 on the light incident side of thewavelength conversion sheet 3 makes it possible to suppress occurrenceof the above-described color unevenness. For example, as illustrated inFIG. 10, when the oblique component L2 enters the diffusion member 4,the light is diffused, and the distribution of the traveling directionangle of the light is uniformized to some extent. As a result, the ratioof the oblique component L2 is reduced, and occurrence of the colorunevenness is suppressed.

(1.3 Effects)

As described above, in the first embodiment, the diffusion member 4 isprovided between the wavelength conversion sheet 3 and the plurality oflight sources 2. Therefore, it is possible to suppress occurrence ofcolor unevenness and to improve quality of illumination light.

Note that the effects described in the present specification are merelyexamples without limitation, and other effects may be obtainable.

(1.4 Modifications of First Embodiment) (1.4.1 First Modification)(Structure)

FIG. 11 illustrates a structure example of a light source deviceaccording to a first modification of the first embodiment. The firstmodification has a structure substantially similar to the structure inFIG. 1 except that a diffuser with a shaped surface 40 is provided asthe diffusion member 4. The diffuser with the shaped surface 40 hasoptical elements each having a predetermined shape. The optical elementsare two-dimensionally formed (molded) on a front surface of the diffuserwith the shaped surface 40. The diffuser with the shaped surface 40 isdisposed so that a side provided with the optical elements each havingthe predetermined shape faces to the wavelength conversion sheet 3.

FIG. 12 illustrates a first structure example of the diffuser with theshaped surface 40. FIG. 13 illustrates an example of a light sourceimage formed by a diffuser with a shaped surface 40A illustrated in FIG.12. In the structure example of the diffuser with the shaped surface40A, fine square pyramid-shaped convex patterns are two-dimensionallyformed as the optical elements each having a predetermined shape. Insuch a diffuser with the shaped surface 40A, the light source image fromone light source 2 is blanched to four images and collected, byrefraction function of the plurality of square pyramid-shaped convexpatterns. As a result, as illustrated in FIG. 13, a light source image91 for one light source 2 appears directly above the light source 2 onthe diffuser with the shaped surface 40A and four collected-light images92 appear around the light source image 91, and thus it seems as if thenumber of light sources 2 is increased fivefold.

FIG. 14 illustrates a second structure example of the diffuser with theshaped surface 40. FIG. 15 illustrates an example of a light sourceimage formed by a diffuser with a shaped surface 40B illustrated in FIG.14. In the structure example of the diffuser with the shaped surface40B, fine triangular pyramid-shaped convex patterns aretwo-dimensionally formed as the optical elements each having apredetermined shape. In such a diffuser with the shaped surface 40B, byrefraction function by the plurality of triangular pyramid-shaped convexpatterns, as illustrated in FIG. 15, the light source image 91 for onelight source 2 appears directly above the light source 2 on the diffuserwith the shaped surface 40B and six collected-light images appear aroundthe light source image 91, and thus it seems as if the number of lightsources 2 is increased sevenfold.

(Function and Effects)

Function and Effects obtained by using the diffuser with the shapedsurface 40 are described below.

When the diffuser with the shaped surface 40 is omitted from thestructure, in the wavelength conversion sheet 3, luminance differenceoccurs between a region directly above the light source 2 and a regionbetween adjacent light sources 2, and luminance unevenness occurs.Hereinafter, such luminance unevenness is referred to as “granularunevenness”. To dissolve the granular unevenness, there is a method inwhich a post-attached lens 24 is provided to the light source 2 as witha light source device according to a comparative example illustrated inFIG. 16. Also in the light source device according to the comparativeexample, as with the case described with use of FIG. 5, the downwardlight LB1 and LY1 from the wavelength conversion sheet 3 and the opticalsheet 5 are reflected by the reflective sheet 6 on the light sourcedevice 1, and are used as recycle light to generate white light.However, when the post-attached lens 24 is provided on the light source2, it is necessary to increase the size of the through hole 61 (see FIG.2 and FIG. 3) provided on the reflective sheet 6 by the size of thepost-attached lens 24. Therefore, as compared with a case where thepost-attached lens 24 is not provided on the light source 2, an area ofthe reflective sheet 6 is decreased, which reduces utilizationefficiency of the recycle light. Accordingly, degradation in entireluminance occurs.

On the other hand, when the diffuser with the shaped surface 40 is used,the apparent number of light sources 2 is allowed to be increased asdescribed above. Therefore, it is possible to dissolve the granularunevenness without using the post-attached lens 24 as illustrated inFIG. 16. In this case, since the post-attached lens 24 is not used,decrease in area of the reflective sheet 6 as described above does notoccur. Accordingly, it is possible to dissolve the granular unevennesswithout degrading the entire luminance, as compared with the case wherethe post-attached lens 24 is used.

(1.4.2 Second Modification) (Structure)

FIG. 17 illustrates a structure example of a light source deviceaccording to a second modification of the first embodiment. The secondmodification has a structure substantially similar to the structureexample in FIG. 1 except that a direct potting type light sources 2A aredisposed. FIG. 18 illustrates a structure example of each of the directpotting type light sources 2A. The direct potting type light source 2Ahas a structure in which a light emitting element chip 13 (for example,an LED dice) is only potted on the light source substrate 1 by asealant, and is decreased in an area as compared with the packaged lightsource 2 as illustrated in FIG. 3. The light source 2A includes thelight emitting element chip 13 and a sealing lens 12 formed by a sealantthat seals the light emitting element chip 13 on the light source device1.

In the structure example illustrated in FIG. 18, a light reflectivewiring pattern 14 is formed on the front surface of the light sourcedevice 1. For example, the wiring pattern 14 may include a wiring layer14A and a wiring layer 14B that are to supply a drive current to thelight emitting element chip 13 and a chip mounting layer 14C that is tomount the light emitting element chip 13. The wiring layers 14A and 14Band the chip mounting layer 14C are formed of a material havingconductivity and light reflectivity by the same step, and areelectrically independent of one another. Note that the chip mountinglayer 14C may have only a function as a base of the light emittingelement chip 13 and may not have a function as a wiring. In this case,for example, “light reflectivity” indicates a case where a material hasa reflectance to light (back surface emitted light) emitted from thelight emitting element chip 13 equal to or higher than 90%, and specificexamples of the material having such light reflectivity may include, forexample, Al, Ag, and an alloy thereof.

The light emitting element chip 13 is electrically connected to thewiring layers 14A and 14B through wirings (bonding wires) 15A and 15Bsuch as Al and Ag. The light emitting element chip 13 is driven by acurrent flowing through the wiring layers 14A and 14B and the wirings15A and 15B, and emits light.

The light emitting element chip 13 is mounted directly on the chipmounting layer 14C. In this case, “directly” indicates that the backsurface of the light emitting element chip 13 is bonded to the chipmounting layer 14C by die bonding or the like without packaging thelight emitting element chip 13 or providing a reflective layer such as atin or gold plating layer between the chip mounting layer 14C and thelight emitting element chip 13. However, an adhesive layer such astransparent paste 16 for die bonding may be interposed between the chipmounting layer 14C and the light emitting element chip 13. Incidentally,although the transparent paste 16 does not have conductivity, when anLED chip having electrodes on both surfaces is used, the transparentpaste 16 may have conductivity because the chip mounting layer 14C has afunction as a current path.

For example, the resist layer 7 may be formed as a solid film on theentire surface of the light source substrate 1 other than a regionmounted with the light emitting element chip 13 and a region where thelight emitting element chip 13 is connected to the wiring layers 14A and14B. The reflective sheet 6 is disposed on the resist layer 7. As withthe structure example of FIG. 2 and FIG. 3, the through holes 61 wherethe light sources 2A are disposed are formed on the reflective sheet 6.In the in-plane region provided with the through holes 61, the resistlayer 7 is exposed around the light sources 2A. Therefore, the outermostsurface of the light source substrate 1 is the reflective sheet 6 in thein-plane region other than the through holes 61, and is the lightsources 2A and the resist layer 7 in the in-plane region provided withthe through holes 61.

The sealing lens 12 protects the light emitting element chip 13 andimproves extraction efficiency of light L emitted from the lightemitting element chip 13. The sealing lens 12 is formed of a sealant(for example, a transparent resin such as silicone and acryl) so as tocover the entire light emitting element chip 13.

The sealing lens 12 is formed in a dome lens shape by the sealant. For areason described later, in terms of a height h and a radius r of thedome lens shape, the sealing lens 12 may preferably satisfy thecondition of 0.65≦h/r≦1.

In the light source 2A, the light emitted from the light emittingelement chip 13 is extracted frontward through the sealing lens 12, andpart of the light travels from the back surface side of the lightemitting element chip 13 to the light source substrate 1 side (the backsurface emitted light). The back surface emitted light L is reflected bythe front surface of the chip mounting layer 14 that is mounted with thelight emitting element chip 13 and has a high light reflection function,and is then extracted frontward as illustrated in FIG. 18.

(Function and Effects)

A function and effects obtained by using the direct potting type lightsources 2A is described below.

In a normal planar light source device, for example, a white LED packagein which a sealant mixed with a fluorescent substance that converts awavelength of light into a wavelength of yellow, or green and red ismounted on a blue LED chip is used as the light source. In this case,light emitted from (wavelength-converted by) the fluorescent substanceis emitted in all directions. In addition, blue light that is notabsorbed by the fluorescent substance and is reflected by the surface ofthe fluorescent substance is also reflected in all directions. In otherwords, the sealant itself functions as the fluorescent substance, andthe extraction efficiency of light from the LED package is not greatlyvaried depending on the sealant, namely, the lens shape. However, in thepresent embodiment, as with the structure example in FIG. 1 and FIG. 3,when the wavelength conversion sheet 3 is oppositely disposed separatelyfrom the light source 2 and the translucent sealant 23 is used for thelight source 2, the outer shape of the sealant 23 has a largeimplication of a function as a lens to extract light emitted from thelight emitting element 21. At this time, a lens shape of a currenttypical white LED package is substantially flat. When the blue LEDpackage having the shape of the white package, in which only thefluorescent substance is eliminated from the sealant is combined as thelight source 2 with the wavelength conversion sheet 3, extractionefficiency of blue light is deteriorated and thus luminance is notincreased.

In the case where the above-described blue LED package is considered tobe used as the light source 2 to be combined with the wavelengthconversion sheet 3, a lens (a sealant) on the normal LED package mainlyhas a flat shape. Although a small number of dome lenses are produced,an aspect ratio thereof is typically about 0.5 to about 0.6. In thisexample, the aspect ratio is a ratio of the height h and the radius r ofthe dome lens shape, namely, h/r. When the aspect ratio is 1, the shapeis hemisphere shape.

In the case of the above-described blue LED package, the blue light isemitted from an LED chip smaller than the lens diameter. Therefore, inthe case where the LED chip is assumed to be a point light source to thelens, in a flat lens shape, for example, when a refractive index ofsilicone as the lens material is assumed to be n=1.45, light at an angleof θ=43.6 degrees or more that is emitted from the LED chip is totallyreflected and is returned to a bottom side, and is emitted to theoutside of the package after being repeatedly reflected by side walls ora bottom surface in the package. In this way, since the part of light isrepeatedly reflected in the package, which results in degradation ofluminance efficiency. In contrast, in the LED package having thehemispherical dome lens, most of the light emitted from the LED chiplocated at the center of the lens directs in a normal direction to thelens outer shape, and therefore, the light is scarcely reflected and isemitted as it is. Accordingly, luminance efficiency becomes high.

Since the light source 2A according to the present modification has thedirect potting type structure, the sealing lens 12 is easily formed in adome shape having an aspect ratio of 0.65 or more and 1 or less, andthus the luminance efficiency is allowed to be increased. Moreover, therefractive index of the sealant (for example, silicone) is increased tobe close to the refractive index of the base material (for example,sapphire) of the light emitting element chip 13, which makes it possibleto suppress reflection between the light emitting element chip 13 andthe sealant to further increase the luminance efficiency. Furthermore,it is possible to achieve dome-shaped LED package at a price lower thanthat of a normal LED package that is not of the direct potting type.

Table 1 illustrates a comparison results between the extractionefficiency of the blue light in the case where the direct potting typelight source 2A is used and the extraction efficiency of the blue lightin the case where the normal LED package (the normal PKG) that is not ofthe direct potting type. PKG indicates a package. The blue LED chip isused as the light emitting element chip 13, and silicone is used as thesealant. As is apparent from Table 1, when the lens shape is formed in adome shape, the extraction efficiency is improved. In addition, when theaspect ratio is close to 1, the extraction efficiency is improved. As aresult, when the direct potting type light source 2A according to thepresent modification is used, the extraction efficiency of the bluelight is improved, and thus luminance efficiency is increased.

TABLE 1 Refractive Efficiency Efficiency PKG Chip size Lens Aspect indexof before sealing after sealing Extraction Efficiency shape (μm) shaperatio sealant (μW/W) (μW/W) efficiency ratio Direct 350 × 550 Dome 0.851.52 324712 398494 123% 1 Potting 0.65 1.52 375367 116% 0.94 Normal 335× 575 Plane 0 1.41 272851 264556  97% 0.79 PKG 0 1.52 231332 203341  88%0.72 Dome 0.55 1.41 272851 312700 115% 0.93 0.55 1.52 277962 283700 102%0.83

Also in the light source device according to a second embodiment, aswith the case described with use of FIG. 5, the downward light LB1 andLY1 from the wavelength conversion sheet 3 and the optical sheet 5 arereflected by the reflective sheet 6 on the light source substrate 1 tobe used as recycle light to generate white light. At this time, in thecase where the direct potting type light source 2A is used, the packagearea is allowed to be smaller than that of the normal LED package.Therefore, the size of the through hole 61 provided on the reflectivesheet 6 is allowed to be reduced by that amount. Accordingly, ascompared with the case where the normal LED package is used, the area ofthe reflective sheet 6 is allowed to be increased, which makes itpossible to increase utilization efficiency of the recycle light. As aresult, it is possible to improve luminance of the entire light sourcedevice.

2. Second Embodiment (2.1 Structure)

FIG. 19 illustrates a structure example of a light source deviceaccording to a second embodiment. The light source device according tothe second embodiment has a structure substantially similar to thestructure of FIG. 1 except that a prism sheet 8 is additionally disposedbetween the wavelength conversion sheet 3 and the diffusion member 4.

FIG. 20 illustrates a structure example of the prism sheet 8 in thelight source device. For example, as the prism sheet 8, a cross prismsheet that is obtained by combining a first prism sheet 8A and a secondprism sheet 8B illustrated in FIG. 20 may be used. Alternatively, eitherone of the first prism sheet 8A and the second prism sheet 8B may beused. A plurality of prisms 51 each extending in a first direction Y1are formed on a surface of the first prism sheet 8A. A plurality ofsecond prisms 52 each extending in a second direction X1 that intersectsthe first direction Y1 are formed on a surface of the second prism sheet8B.

(2.2 Function and Effects)

FIG. 21 illustrates a function of the prism sheet 8. For example, asillustrated in FIG. 21, when the oblique component L2 enters the prismsheet 8, the prism sheet 8 allows an angle of the light to rise up in avertical direction or a substantially vertical direction, and emits thelight. Accordingly, occurrence of color unevenness at the time ofperforming local light emission control (local dimming) as describedbelow is suppressed.

As described with use of FIG. 6, when all of the plurality of lightsources 2 emit light, color unevenness is dissolved by making thearrangement distance D of the plurality of light sources 2 small ormaking the distance H between the plurality of light sources 2 and thewavelength conversion sheet 3 large to establish a state where thevertical component L1 and the oblique component L2 of the light from thelight source 2 are uniformly mixed in the wavelength conversion sheet 3.Moreover, as described in the above-described first embodiment, thediffusion member 4 is disposed below the wavelength conversion sheet 3,which makes it possible to dissolve color unevenness.

On the other hand, when the local dimming is performed, non-lightingpart and finely-lighting part are generated in the plurality of lightsources 2, and thus difference in light emission distribution of theplurality of light sources 2 is generated. In this case, intensitydifference is generated for each optical path of light (for example,blue light) that enters the wavelength conversion sheet 3 from therespective light sources 2, and color unevenness in which thenon-lighting part and the finely-lighting part turn yellow as comparedwith normal lighting part occurs. Moreover, in a state where the localdimming is performed, from above the light source 2 that emits light atnormal intensity, light returning from the wavelength conversion sheet 3and the optical sheet 5 to the back side (the substrate 1 side) isreflected while being diffused by the reflective sheet 6, is then spreadto the front side of the non-lighting part and the finely-lighting part,and then returns to the wavelength conversion sheet 3 side again. Thereturned light passes through the wavelength conversion sheet 3 again,and for example, may be converted into green light or red light with useof part of blue light (while decreasing the blue light). Therefore, thelight after passing through the wavelength conversion sheet 3 that isgenerated by returned light becomes yellowish, which enhances yellowcoloring of the non-lighting part and the finely-lighting part. As aresult, when it is applied to the display unit, an image at thefinely-lighting luminance display part by the local dimming becomesyellowish to impair dignity. Note that, when it is used as a backlightof a liquid crystal display unit, color change to yellow by a planarlight source is not observed because a pixel opening by liquid crystalis closed at a black display part. According to the second embodiment,it is possible to suppress occurrence of color unevenness at the time ofthe above-described local dimming, by a function of the prism sheet 8.

3. Third Embodiment (3.1 Structure and Function)

FIG. 22 illustrates a structure example of a light source deviceaccording to a third embodiment. The light source device according tothe third embodiment has a structure substantially similar to that inFIG. 1 except that a cut filter 9 is additionally disposed on the lightsource substrate 1. The cut filter 9 is disposed so as to cover thesurface of the reflective sheet 6. The cut filter 9 is an optical filterthat allows the light (for example, blue light) emitted from the lightsource 2 to pass therethrough and cuts light (for example, red light andgreen light, or yellow light) that is wavelength-converted by thewavelength conversion sheet 3. The cut filter is not necessarily afilter completely cutting light that is wavelength-converted by thewavelength conversion sheet 3, and it is only necessary for the cutfilter 9 to have characteristics in which transmittance to the lightwavelength-converted by the wavelength conversion sheet 3 is lower thanthe transmittance to the light emitted from the light source 2.

FIG. 23 illustrates a function of the cut filter 9. In the case of thestructure of FIG. 5, the downward light LB1 returning to the lightsource substrate 1 side, out of the light LB emitted from the lightsource 2, is reflected by the reflective sheet 6, and directs toward thewavelength conversion sheet 3 again. Likewise, the downward light LY1out of the wavelength-converted light LY is also reflected by thereflective sheet 6 and directs toward the wavelength conversion sheet 3again. On the other hand, in the structure of the third embodiment, asillustrated in FIG. 23, reflection of the wavelength-converted downwardlight LY1 is suppressed by provision of the cut filter 9. The downwardlight LB1 not wavelength-converted passes through the cut filter 9 to bereflected by the reflective sheet 6, and then directs toward thewavelength conversion sheet 3 again.

As described in the above-described second embodiment, when the localdimming is performed, the non-lighting part and the finely-lighting partare generated in the plurality of light sources 2, which causes colorunevenness in which the non-lighting part and the finely-lighting partbecome, for example, yellowish as compared with the normal lightingpart. According to the third embodiment, providing the cut filter 9makes it possible to suppress reflection of the wavelength-converteddownward light LY1 (for example, yellow light), and thus yellow lightreused as recycle light is decreased. Accordingly, occurrence of colorunevenness to yellowish is suppressed.

(3.2 Modification of Third Embodiment)

FIG. 24 and FIG. 25 each illustrate a structure example of a lightsource device according to a modification of the third embodiment. Asillustrated in FIG. 24, a structure combined with the structure of theabove-described second embodiment (FIG. 19) may be employed. In otherwords, a structure including the prism sheet 8 and the cut filter 9 maybe employed. In addition, as illustrated in FIG. 25, for example, areflective sheet 6A with filter function, which is obtained by providingthe function of the cut filter 9 to the reflective sheet 6 throughcoloring, may be disposed. The reflective sheet 6A with the filterfunction is not necessarily a reflective sheet that completely cuts thelight wavelength-converted by the wavelength conversion sheet 3, and itis only necessary for the reflective sheet 6A to have filtercharacteristics allowing reflectance to the light wavelength-convertedby the wavelength conversion sheet 3 to be lower than the reflectance tothe light emitted from the light source 2. For example, the reflectivesheet 6A may have filter characteristics that allow reflectance of greenlight and red light that are wavelength converted, to be lower by about21% or more than the reflectance of the blue light emitted from thelight source 2. For example, when the reflectance of the blue light isabout 95%, the reflectance of green light and red light may bepreferably about 75% or less. In this case, the reflectance of greenlight and red light is lower by 1−(75/95)=21% or more than thereflectance of the blue light.

4. Numerical Examples

Effects of luminance improvement by dissolving the granular unevennessin the first modification of the first embodiment described above (inthe structure example in which the diffuser with the shaped surface 40is disposed as the diffusion member 4) were specifically simulated.Simulation results are illustrated in Table 2 and Table 3.

Table 2 and Table 3 illustrate results obtained by methods of dissolvinggranular unevenness that are roughly divided into following threemethods.

Method 1: a structure in which the post-attached lens 24 (see FIG. 16)is provided in the light source 2 (with the normal diffusion member 4)

Method 2: a structure in which the diffuser with the shaped surface 40is disposed (without the post-attached lens 24)

Method 3: a structure in which only the normal diffusion member 4 isdisposed (a method in which the granular unevenness is eliminated byincreasing the number of LEDs as the light sources 2A without providingthe post-attached lens 24)

As a structure common to the respective methods, cross-arranged twoprism sheets and the DBEF were disposed as the optical sheet 5, inaddition to the normal diffusion member 4 or the diffuser with theshaped surface 40. Moreover, an optical distance between the lightsources 2 or 2A and the wavelength conversion sheet 3 was set to 16 mm.The entire size of the light source device was 55 inches.

The calculation was made assuming that the number of LEDs as the lightsources 2 or 2A necessary for dissolving the granular unevenness was asfollows:

Method 1: 680 piecesMethod 2: 832 piecesMethod 3: 1360 pieces

Moreover, in the respective methods described above, the calculation wasmade assuming that the package size (PKG size) of the LED as the lightsource 2 was as follows. Note that, in the method 1, the direct pottingtype structure is not provided.

Normal size: 3.2 mm×2.85 mm

Small size 1: 4 mm×2 mm

Small size 2: 3 mm×1.4 mm

Direct potting type (Dir P): φ3 mm

The following values were used as the other conditions.

Transmittance of post-attached lens 24 (acryl): 93%Reflectance of reflective sheet 6: 98%Reflectance of resist layer 7: 70%Reflectance of LED package (normal and small size): 88%Reflectance of direct potting type LED package: 81%Reflectance of LED package below post-attached lens 24: 79.4%Reflectance of resist layer 7 below post-attached lens 24: 86.4%

Incidentally, as described above, in the reflective sheet 6, the throughholes 61 to dispose the light sources 2 or 2A are formed. Therefore, inthe region of the through holes 61, exposed surfaces of the resist layer7 are provided around the light sources 2 or 2A. In Table 2, resultsobtained by calculating respective area ratios occupied by LED package,the exposed surfaces of the resist layer 7, the reflective sheet 6, andthe like, on the outermost surface of the light source substrate 1 areillustrated for each method.

In Table 3, reflectance of the entire region of the outermost surface onthe light source substrate 1 as a whole is illustrated as a total (TTL)reflectance. In addition, as described above, light recycle is performedbetween the light source substrate 1 and both of the wavelengthconversion sheet 3 and the optical sheet 5 by reflection on the lightsource substrate 1. The inventor of the present application confirmedfrom experiment that luminance as the light source device is obtained byperforming recycle four times. In other words, since reflection isperformed four times on the light source substrate 1, fourth power ofthe TTL reflectance is calculated. The value of the fourth power of theTTL reflectance corresponds to final luminance. In Table 3, to comparedifference in final luminance, results obtained by comparing andcalculating the fourth power of the TTL reflectance for each method andfor each size of the LED package are illustrated.

It is found from the simulation results that using the diffuser with theshaped surface 40 is advantageous in luminance improvement irrespectiveof the size and form of the LED package. Moreover, in the respectivemethods, it is found that when the distance of opposing corners of theLED package or the size φ of the direct potting type light source isequal to or smaller than 77% of the size of the normal LED package, thearea ratio occupied by the reflective sheet 6 is increased, and theluminance is accordingly improved. In this example, the size of theopposing corners of the normal LED package is 4.3 mm, the size of theopposing corners of the LED package of the above-described small size 2is 3.3 mm, and the ratio thereof is 0.77.

TABLE 2 Area ratio and premise reflectance PKG surface out Surface ofMethod of PKG surface Resist surface Exposed surface of lens reflectivedissolving below lens below lens of resist layer Reflectance sheetgranular Reflectance Reflectance Reflectance PKG: 90% Reflectanceunevenness PKG size 79.4% 86.4% 70% Dir P: 80% 98% Post-attached Normal0.74% 14.50% 6.47% — 78.29% lens Small size 0.65% 15.95% 6.73% — 76.67%1 Small size 0.34%  8.76% 6.73% — 84.17% 2 Diffuser with Normal — —4.32% 0.90% 94.78% shaped Small size — — 3.54% 0.79% 95.67% surface 1Small size — — 2.68% 0.42% 96.91% 2 Dir P — — 2.10% 0.70% 97.21% Onlynormal Normal — — 7.06% 1.47% 91.47% diffuser Small size — — 5.79% 1.29%92.92% 1 Small size — — 4.37% 0.68% 94.95% 2 Dir P — — 3.43% 1.14%95.43%

TABLE 3 Method of dissolving Fourth-power granular of TTL unevenness PKGsize TTL Reflectance Reflectance Fourth-power reflectance ratioPost-attached Normal 91.3% 69.5% Ref lens Small size 90.8% 67.9% 0.98 1Small size 93.2% 75.4% 1.09 2 Diffuser with Normal 96.7% 87.4% 1.26 Refshaped Small size 96.7% 87.5% 1.26 1.00 surface 1 Small size 97.2% 89.3%1.29 1.02 2 Dir P 97.3% 89.6% 1.29 1.02 Only normal Normal 95.9% 84.5%1.22 Ref diffuser Small size 96.3% 85.8% 1.24 1.02 1 Small size 96.7%87.5% 1.26 1.04 2 Dir P 96.8% 88.0% 1.27 1.04

5. Other Embodiments

The technology of the present disclosure is not limited to thosedescribed in the respective embodiments, and is variously modified.

For example, the light source device according to any of theabove-described embodiments may be applied as a backlight of a displayunit 201 as illustrated in FIG. 26. The display unit 201 includes adisplay section 202 and a stand 203. The display section 202 mayinclude, for example, a transmission type liquid crystal display panel,and displays an image based on illumination light from a backlight thatis disposed on a back surface side of the display section 202. The lightsource device according to any of the above-described respectiveembodiments may be applied as such a back light.

For example, the present technology may be configured as follows:

(1) A light source device including:

a substrate;

a plurality of light sources disposed on the substrate;

a wavelength conversion member disposed to face the plurality of lightsources; and

a diffusion member disposed between the wavelength conversion member andthe plurality of light sources, and configured to uniformizedistribution of traveling direction angle of incident light.

(2) The light source device according to (1), wherein the diffusionmember is a diffuser with a shaped surface.

(3) The light source device according to (2), wherein the diffuser withthe shaped surface has optical elements two-dimensionally arranged on asurface, each of the optical elements having a predetermined shape.

(4) The light source device according to any one of (1) to (3), whereineach of the light sources has a light emitting element chip and asealant that seals the light emitting element chip on the substrate.

(5) The light source device according to (4), wherein a dome lens isformed of the sealant and a following condition is satisfied,

0.65≦h/r≦1

where h is a height of the dome lens and r is a radius of the dome lens.

(6) The light source device according to any one of (1) to (5), furtherincluding

a first prism sheet disposed between the wavelength conversion memberand the diffusion member and having a plurality of first prisms on asurface, each of the plurality of first prisms extending in a firstdirection.

(7) The light source device according to (6), further including

a second prism sheet disposed between the wavelength conversion memberand the diffusion member, and having a plurality of second prisms on asurface, each of the plurality of second prisms extending in a seconddirection orthogonal to the first direction.

(8) The light source device according to any one of (1) to (7), furtherincluding:

a reflective member disposed in a region on the substrate, the regionbeing different from a region provided with the plurality of lightsources; and

a cut filter disposed to cover the reflective member and having filtercharacteristics, the filter characteristics allowing a transmittance tolight that is wavelength-converted by the wavelength conversion member,to be lower than a transmittance to light emitted from each of the lightsources.

(9) The light source device according to any one of (1) to (7), furtherincluding

a reflective member disposed in a region on the substrate, the regionbeing different from a region provided with the plurality of lightsources, wherein

the reflective member has filter characteristics allowing a reflectanceto light that is wavelength-converted by the wavelength conversionmember, to be lower than a reflectance to light emitted from each of thelight sources.

(10) The light source device according to any one of (1) to (9), whereinthe plurality of light sources are two-dimensionally arranged on thesubstrate.

(11) The light source device according to (10), wherein the plurality oflight sources are placed under individual light emission control forevery one light source or every two or more light sources.

(12) The light source device according to any one of (1) to (11),wherein each of the plurality of light sources includes a light emittingelement configured of an LED.

(13) The light source device according to any one of (1) to (12),wherein

the light sources each configured to emit blue light, and

the wavelength conversion member converts part of blue light emittedfrom the light sources into red light and green light.

(14) The light source device according to any one of (1) to (12),wherein

the light sources each configured to emit blue light, and

the wavelength conversion member converts part of blue light emittedfrom the light sources into yellow light.

(15) A display unit provided with a light source device configured toemit illumination light and a display section configured to display animage based on the illumination light from the light source device, thelight source device including:

a substrate;

a plurality of light sources disposed on the substrate;

a wavelength conversion member disposed to face the plurality of lightsources; and

a diffusion member disposed between the wavelength conversion member andthe plurality of light sources, and configured to uniformizedistribution of traveling direction angle of incident light.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations, and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

What is claimed is:
 1. A light source device comprising: a substrate; aplurality of light sources disposed on the substrate; a wavelengthconversion member disposed to face the plurality of light sources; and adiffusion member disposed between the wavelength conversion member andthe plurality of light sources, and configured to uniformizedistribution of traveling direction angle of incident light.
 2. Thelight source device according to claim 1, wherein the diffusion memberis a diffuser with a shaped surface.
 3. The light source deviceaccording to claim 2, wherein the diffuser with the shaped surface hasoptical elements two-dimensionally arranged on a surface, each of theoptical elements having a predetermined shape.
 4. The light sourcedevice according to claim 1, wherein each of the light sources has alight emitting element chip and a sealant that seals the light emittingelement chip on the substrate.
 5. The light source device according toclaim 4, wherein the sealant is formed into a dome lens and a followingcondition is satisfied,0.65≦h/r≦1 where h is a height of the dome lens and r is a radius of thedome lens.
 6. The light source device according to claim 1, furthercomprising a first prism sheet disposed between the wavelengthconversion member and the diffusion member and having a plurality offirst prisms on a surface, each of the plurality of first prismsextending in a first direction.
 7. The light source device according toclaim 6, further comprising a second prism sheet disposed between thewavelength conversion member and the diffusion member, and having aplurality of second prisms on a surface, each of the plurality of secondprisms extending in a second direction orthogonal to the firstdirection.
 8. The light source device according to claim 1, furthercomprising: a reflective member disposed in a region on the substrate,the region being different from a region provided with the plurality oflight sources; and a cut filter disposed to cover the reflective memberand having filter characteristics, the filter characteristics allowing atransmittance to light that is wavelength-converted by the wavelengthconversion member, to be lower than a transmittance to light emittedfrom each of the light sources.
 9. The light source device according toclaim 1, further comprising a reflective member disposed in a region onthe substrate, the region being different from a region provided withthe plurality of light sources, wherein the reflective member has filtercharacteristics allowing a reflectance to light that iswavelength-converted by the wavelength conversion member, to be lowerthan a reflectance to light emitted from each of the light sources. 10.The light source device according to claim 1, wherein the plurality oflight sources are two-dimensionally arranged on the substrate.
 11. Thelight source device according to claim 10, wherein the plurality oflight sources are placed under individual light emission control forevery one light source or every two or more light sources.
 12. The lightsource device according to claim 1, wherein each of the plurality oflight sources includes a light emitting element configured of an LED.13. The light source device according to claim 1, wherein the lightsources each configured to emit blue light, and the wavelengthconversion member converts part of blue light emitted from the lightsources into red light and green light.
 14. The light source deviceaccording to claim 1, wherein the light sources each configured to emitblue light, and the wavelength conversion member converts part of bluelight emitted from the light sources into yellow light.
 15. A displayunit provided with a light source device configured to emit illuminationlight and a display section configured to display an image based on theillumination light from the light source device, the light source devicecomprising: a substrate; a plurality of light sources disposed on thesubstrate; a wavelength conversion member disposed to face the pluralityof light sources; and a diffusion member disposed between the wavelengthconversion member and the plurality of light sources, and configured touniformize distribution of traveling direction angle of incident light.